Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes

Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Senlin; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

doi:10.1016/j.watres.2018.03.004

Cited by 154 publications

(75 citation statements)

References 43 publications

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“…The V. fischeri toxicity was decreased by UV/chlorine treatment in three researches [72][73][74]. However, an increase in toxicity was reported in the rest of three [21,37,40]. One of reasons of the discrepancy may be treatment time in UV/chlorine AOPs.…”

Section: Inactivation Of Microbesmentioning

confidence: 90%

“…Information on reaction mechanism of ClO˙ is relatively limited compared with other RCS. Kong et al reported that degradation of gemfibrozil by ClO˙ is initiated by hydroxylation and chlorine substitution on the benzene ring [37]. Alfassi et al discussed the kinetics of ClO˙ and suggested that ClO˙ abstracts an electron from an organic compound and produces an organic radical like equation (10), but H-abstraction or addition reaction is difficult to occur [18].…”

Section: Reactive Radical Speciesmentioning

confidence: 99%

“…Some researchers applied this method for UV/chlorine AOPs to estimate the contribution of reactive species [20,23,31,37,40]. However, the addition of chemical probes affects both the degradation rate of pollutant and the steadystate concentration of reactive species through competitive consumption of reactive species.…”

Section: ( )mentioning

confidence: 99%

“…Chlorinated organic compounds like halomethanes (HMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), halonitoromethanes (HNMs), haloacetamides (HAAms), and chloral hydrate (CH) are well known DBPs by chlorination [49,50] and their formation in UV/chlorine AOPs is thereby apprehended. In fact some researchers reported that UV/chlorine AOPs produced trichloromethane (TCM) and chloroform (CF) in HMs, dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in HAAs, dichloroacetonitrile (DCAN) and trichloroacetonitrile (TCAN) in HANs, dichloropropanone (DCP) and trichloropropanone (TCP) in HKs, chloronitoromethane (CNM), dichloronitoromethane (DCNM), and trichloronitromethane (TCNM) in HNMs, dichloroacetamide (DCAAm) and trichloroacetamide (TCAAm) in HAAms, and CH [20][21][22]37,47,[51][52][53][54][55]. Some comparative studies of UV/chlorine process with chlorination have been reported.…”

Section: Chlorinated Organic Compoundsmentioning

confidence: 99%

“…One of reasons of the discrepancy may be treatment time in UV/chlorine AOPs. In researches with reduction in V. fischeri toxicity, the treatment time was not shorter than 1 h [72][73][74], whereas the treatment time was set at 13 min or shorter in the research with the increase in the toxicity [21,37,40]. In UV/chlorine AOPs chlorinated organic byproducts are temporally produced.…”

Section: Inactivation Of Microbesmentioning

confidence: 99%

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State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

Kishimoto

2019

J. of Wat. & Envir. Tech.

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The photolysis of chlorine by ultraviolet radiation (UV/chlorine) produces HO˙ and Cl˙, part of which further transforms into reactive chlorine species (RCS) like Cl 2˙− and ClO˙. These radicals are responsible for the advanced oxidation effect of UV/chlorine processes. Recently, UV/chlorine processes gather much attention from researchers and practitioners and published papers on UV/chlorine processes have drastically increased, which were thoroughly reviewed in this paper for understanding the state of the art of these technologies. Fundamental studies elucidate that acidic conditions are favorable to UV/chlorine processes through a change in quantum yield of chlorine photolysis, equilibrium shifts of radical species, and a change in radical scavenger effect of free chlorine. Comparative studies reveal that UV/chlorine processes are usually more energy-efficient than UV/hydrogen peroxide and UV/ persulfate processes. Although unfavorable byproducts formation by RCS reactions is apprehended, application researches in real waters show that UV/chlorine processes do not enhance disinfection byproducts formation very much. Since UV irradiation and chlorination are widely used unit operations, a barrier to install an UV/chlorine process into a conventional process is not high. It is desired to develop and optimize a whole process combined with other unit processes for maximizing benefits in water treatment in the future. CONTENTS INFLUENTIAL FACTORSEffect of pH Effect of chlorine dose Effect of halide ion Effect of alkalinity Effect of natural organic matter (NOM) Effect of UV light source LP-UV/chlorine process MP-UV/chlorine process Excimer-UV/chlorine process UV-LED/chlorine process Solar/chlorine process Comparison with other UV-based AOPs PROCESS VARIATIONS

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Section: Inactivation Of Microbesmentioning

confidence: 90%

Section: Reactive Radical Speciesmentioning

confidence: 99%

Section: ( )mentioning

confidence: 99%

Section: Chlorinated Organic Compoundsmentioning

confidence: 99%

Section: Inactivation Of Microbesmentioning

confidence: 99%

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State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

Kishimoto

2019

J. of Wat. & Envir. Tech.

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UV/Periodate Advanced Oxidation Process: Fundamentals and Applications

Merouani¹,

Hamdaoui

2021

Applied Water Science

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Fe(III)‐catalyzed degradation of persistent textile dyes by chlorine at slightly acidic conditions: the crucial role of Cl₂^●− radical in the degradation process and impacts of mineral and organic competitors

Meghlaoui¹,

Merouani²,

Hamdaoui

et al. 2020

Asia-Pacific J Chem Eng

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In this work, we have explored for the first time the potential application of trace‐Fe(III)/chlorine system as an innovative oxidation technology for the degradation of persistent textile dyes. Fe(III)/chlorine combination improved the dye removal by ~40% within 30 s, as compared with chlorination alone, mainly through a radical pathway induced by the catalytic activation of chlorine in the presence of Fe(III). A chemical probe method was used for identifying the main reactive species. Cl2●− was found to be the key species responsible of huge abatement of dyes in the Fe(III)/chlorine system, whereas ●OH and Cl● can participate with only ~5% in the overall removal efficiency. At pH 3, 77% of reactive green 12 (RG12) was removed after 30 s, and then the removal efficiency diminished to 60% at pH 4, 20% at pH 5, and ~10% at pH 6 and 7. However, the best implication of free radicals was achieved at pH 4, at which the degradation rate was 3.3 time higher than that of chlorination alone. The dye removal efficiency increased with an increase in chlorine and iron loads up to certain optimums, but detrimental effect was observed at higher dosage levels. An increase in the solution temperature notably accelerated the removal yield (i.e., 81% of RG12 was removed at 50°C against 67% at 30°C and 57% at 10°C). NO2− and HSO3− as well as the cationic surfactant Adogen 464 showed strongest inhibiting effect on the performance of the process. Based on these findings, the Fe(III)/chlorine process is highly efficient in removing dyes from wastewaters.

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Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes

Cited by 154 publications

References 43 publications

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

UV/Periodate Advanced Oxidation Process: Fundamentals and Applications

Fe(III)‐catalyzed degradation of persistent textile dyes by chlorine at slightly acidic conditions: the crucial role of Cl₂^●− radical in the degradation process and impacts of mineral and organic competitors

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Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes

Cited by 154 publications

References 43 publications

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

UV/Periodate Advanced Oxidation Process: Fundamentals and Applications

Fe(III)‐catalyzed degradation of persistent textile dyes by chlorine at slightly acidic conditions: the crucial role of Cl2●− radical in the degradation process and impacts of mineral and organic competitors

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Product

Resources

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Fe(III)‐catalyzed degradation of persistent textile dyes by chlorine at slightly acidic conditions: the crucial role of Cl₂^●− radical in the degradation process and impacts of mineral and organic competitors